Irrigation curtain and erosion control method for regenerative stormwater conveyance

ABSTRACT

In a Regenerative Stormwater Conveyance (RSC) system, rather than increase base flow by putting a horizontal layer of clay and silts in the entire streambed, constructing vertical irrigation curtains with clay rich soil to interrupt the groundwater flow at certain intervals will increase surface water base flows and improve habitat and water quality while also improving the interactions between the hyporheic zones and the channel. Also, by initially providing a subsurface flow channel through which water can flow, for example, using a perforated pipe, and building an access road over that channel during construction, erosion in the RSC project area can be significantly reduced or eliminated.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of prior-filed, co-pending U.S. Provisional Patent Application No. 62/537,750, filed Jul. 27, 2017, the entire contents of which are incorporated by reference.

BACKGROUND

The present disclosure relates to improvements to a Regenerative Stormwater Conveyance (RSC) system and methods therefor. In particular, the disclosure relates to an irrigation curtain and a method of controlling erosion in and around an RSC project site.

A detailed description of RSC construction and operation are provided in U.S. published patent application numbers US 2007/0160424 and US 2009/0290936, both of which are incorporated herein in their entirety and invented by the same inventor as that which is disclosed herein.

SUMMARY

In an RSC system, constructing one or more vertical irrigation curtains with non-porous material, such as clay rich soil, to interrupt the groundwater flow at certain intervals will increase surface water base flows and improve habitat and water quality while also improving the interactions between the hyporheic zones and the channel. Also, by initially providing a subsurface flow channel through which water can flow, for example, using a perforated pipe, and building an access road over that channel during construction, erosion in the RSC project area can be significantly reduced or eliminated.

In one aspect, an irrigation curtain is provided in an RSC to interrupt and control subsurface groundwater flows and support the intended base flow in the RSC channel. More specifically, a channel located in or on the ground at a geographic location and defining a path through which water flows from a first end of the channel to a second end of the channel is provided. At least one riffle weir is also provided which is/are positioned along the channel and arranged to transition water from a first level to a second level that is lower than the first level. Each of the riffle weirs includes a weir pool having first and second ends formed along the channel and is operable to hold water. One or more first rocks are positioned at the first end of the weir pool, each of the first rocks having top and bottom surfaces and front and back sides, wherein the front side of the first rocks faces the first end of the weir pool, and the top surface of at least one of the first rocks is higher than the water level in said weir pool. A plurality of second rocks located adjacent to the back side of the first rocks are also provided in the riffle weirs, wherein the back side of the first rocks faces the second rocks and each of the second rocks is smaller than each of the first rocks.

Further in accordance with this and other aspects, an irrigation curtain is disposed in an area of the channel that includes a hypohereic zone of the channel. The irrigation curtain further including a vertical mass of material disposed beneath a surface of the channel. In some aspects the irrigation curtain is made of white or red clay, which are substantially impervious to water. When the subsurface water flowing under the channel comes into contact with the impervious clay wall, or side, of the irrigation curtain, that water is forced upward towards the ground surface and assists the base flow of the RSC.

Other aspects of the disclosure will become apparent by consideration of the detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C illustrate several views of an irrigation curtain according to one embodiment.

Although aspects have been described with reference to certain embodiments, variations and modifications exist within the scope and spirit of one or more independent aspects as described. Various exemplary features and advantages are set forth in the appended claims.

DETAILED DESCRIPTION

Before any embodiments are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The disclosure is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. Use of “including” and “comprising” and variations thereof as used herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Use of “consisting of” and variations thereof as used herein is meant to encompass only the items listed thereafter and equivalents thereof.

FIGS. 1A-1C illustrate a regenerative storm water conveyance system (RSC) with an irrigation curtain disposed in one of the pools in accordance with an embodiment of the disclosure. Referring to FIG. 1A, which is a top view of the RSC, the irrigation curtain 10 is situated at the downflow side of pool 5 c. That is, the RSC shown in FIGS. 1A-1D in accordance with this exemplary embodiment includes 4 pools, 5 a-5 d and 4 riffle weir structures, 15 a-15 d. Further, in accordance with the embodiment shown, water flows through the RSC system from pool 5 a to pool 5 d, i.e., from left to right while viewing FIG. 1A.

Irrigation curtain 10 is a substantially impervious structure constructed in such a way to encourage ground water to flow from beneath the RSC up through the ground and into one or more of the pools, 5 a-5 d, of the RSC. In the embodiment shown, irrigation curtain 10 is constructed within the stream channel of the RSC by digging a trench, or ditch, substantially perpendicular to the stream channel flow and filling or packing the trench with impervious material such as white or red clay, or in some circumstances, concrete. Other, substantially impervious materials can also be used as long as the material is stable within the RSC structure and permits a significant amount of the ground water flowing in the porous soil layer to travel up to the pool(s) and not travel through, or be retained within, the curtain.

Referring to FIG. 1B, irrigation curtain 10 is approximately 2-4 feet wide and is positioned deep enough within pool 5 c such that the ground water running beneath the RSC structure will run into the side of the irrigation curtain 10 and be forced upward towards the underside of pool 5 c. It should be noted that the size and shape of irrigation curtain 10 depends on the width and depth of the RSC pools in the system to which the irrigation curtain is being placed. As shown in FIG. 1B, the base of irrigation curtain 10 is wider than the top and the side of the curtain 10 is slanted. This structure provides stability to the curtain structure and also helps direct the water up towards the pool. In accordance with one or more embodiments, however, the length of the irrigation curtain is at least as wide as the pool of the RSC into which it is placed.

As water seeps from the pools 5 a-5 c it filters through a layer of compost 20 and further seeps downhill through a sandy soil 24. In FIG. 1B water flow direction is shown by the large arrow. This water flows through the sandy soil 24. Undisturbed substrate 26 is located beneath the sandy soil layer. Not much water flows through this layer and, thus, according to one or more embodiments the trench, or ditch, for forming the irrigation curtain 10 is dug deep enough so it cuts into the substrate layer 26, forming a solid base for the curtain 10.

Note the arrows within FIG. 1B in sandy soil 24 beneath riffle weir 15 b. These arrows denote the water flow from pool 5 b seepage towards the irrigation curtain 10. As taught by applicant's co-pending application Ser. Nos. 11/482,891 and 12/292,642, the riffle weir structure includes a layer of silica cobbles 35 and boulders 40. In accordance with some embodiments a layer of geotextile material 30 is disposed between the cobble layer 35 of the riffle weir structure and the sandy soil 24.

FIG. 1C shows a cross-cut view through the RSC stream channel as cut through irrigation curtain 10. During construction of the RSC system, a subsurface flow channel is created according to certain embodiments through which water can flow. For example, a perforated pipe (not shown) is placed within the RSC channel and an access road is built over the pipe. Accordingly, erosion in the RSC project area is significantly reduced or eliminated.

The exemplary and alternative embodiments and their constituent components described above may be combined and/or modified in a variety of ways and remain consistent with the intended functionality of the disclosure. Furthermore, the steps and number of the various steps illustrated in the figures, specifically FIGS. 1A-1C, may be adjusted from that shown without straying from the spirit of the disclosure.

It should be noted that the present disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, the embodiments set forth herein are provided so that the disclosure will be thorough and complete, and will fully convey the proper scope to those skilled in the art. The accompanying drawings illustrate exemplary embodiments of the disclosure.

Although the present disclosure has been described in terms of particular exemplary and alternative embodiments, it is not limited to those embodiments. Alternative embodiments, examples, and modifications which would still be encompassed by the disclosure may be made by those skilled in the art, particularly in light of the foregoing teachings.

Those skilled in the art will appreciate that various adaptations and modifications of the exemplary and alternative embodiments described above can be configured without departing from the scope and spirit of that which is disclosed. Therefore, it is to be understood that, within the scope of the appended claims, that which is disclosed and claimed may be practiced other than as specifically described herein. 

What is claimed is:
 1. A system comprising: a channel located in or on the ground at a geographic location and defining a path through which water flows from a first end of said channel to a second end of said channel; at least one riffle weir positioned along said channel and arranged to transition water from a first level to a second level that is lower than the first level, each of said riffle weirs including, a weir pool having first and second ends formed along said channel and being operable to hold water; one or more first rocks positioned at the first end of said weir pool, each of said first rocks having top and bottom surfaces and front and back sides, wherein the front side of said first rocks faces the first end of said weir pool and the top surface of at least one of said first rocks is higher than the water level in said weir pool; and a plurality of second rocks located adjacent to the back side of said first rocks, wherein the back side of said first rocks faces said second rocks and wherein each of said second rocks is smaller than each of said first rocks; and an irrigation curtain disposed in an area of said channel that includes a hypohereic zone of said channel, said irrigation curtain further including a vertical mass of material disposed beneath a surface of said channel.
 2. The system recited in claim 1 wherein said vertical mass includes a clay material.
 3. A regenerative stormwater conveyance system comprising: at least one pool in which water is disposed; a riffle weir structure disposed adjacent to said at least one pool; a layer of porous soil disposed beneath both of said at least pool and said riffle weir structure, wherein water disposed within said pool seeps into said layer of porous soil; an irrigation curtain disposed within said layer of porous soil and configured to direct water within said porous soil into one or more of said at least one pool.
 4. A regenerative stormwater conveyance system as claimed in claim 3, wherein said irrigation curtain is made of substantially impervious material.
 5. A regenerative stormwater conveyance system as claimed in claim 4, wherein said irrigation curtain is made of clay.
 6. A regenerative stormwater conveyance system as claimed in claim 4, wherein said irrigation curtain is made of clay.
 7. A regenerative stormwater conveyance system as claimed in claim 4, wherein said irrigation curtain is made of concrete.
 8. A regenerative stormwater conveyance system as claimed in claim 3, wherein said irrigation curtain is positioned at the downflow side of said at least one pool and a top side of said irrigation curtain is below a top surface of said water within said pool.
 9. A regenerative stormwater conveyance system as claimed in claim 3, wherein said irrigation curtain is wider at a bottom portion thereof than at a top portion thereof and a side portion deflects ground water upwards. 